Here we report the room temperature synthesis of stable CuNi bimetallic alloy particles under aqueous conditions using cetyltrimethylammonium bromide surfactant and hydrazine hydrate as a reducing agent. The bimetallic particles are formed in situ by the reduction of Ni2+ ions to Ni0 by hydrazine. No additional base is added to maintain the pH of the aqueous solution during the synthesis. The reduction process is favoured by Cu nuclei which formed initially. Metallic Cu nuclei assist the growth of CuNi alloy particles of all compositions with nickel-rich kernel phases. The oxidation and hydrogen uptake behaviour of the CuNi particles are found to differ significantly due to the size and intrinsic variations in composition. CuNi particles are also embedded in SBA-15 matrix by similar co-reduction method. The catalytic properties of pristine and SBA-15 grafted CuNi bimetallic systems are studied by p-nitrophenol reduction. © 2014 Elsevier Inc. All rights reserved.

Gangavarapu Ranga Rao

Department Of Chemistry

P. Hari Krishna Charan

Hydrates

Hydrazine

Nickel

Phenols

Aqueous synthesis

CUNI

Nitrophenols

Room temperature

SBA-15

Catalyst activity

IIT Madras is a public technical and research university located in Chennai, Tamil Nadu. Founded in 1959, it is recognised as an Institute of National Importance.

IIT Madras has been ranked as the top engineering institute in India for four years in a row by the National Institutional Ranking Framework of the MHRD

It currently offers undergraduate, postgraduate and research degrees across 16 disciplines in Engineering, Sciences, Humanities and Management. About 596 faculty belonging to science and engineering departments and centres of the Institute are engaged in teaching, research and industrial consultancy.

IIT Madras

Microporous and Mesoporous Materials

Abstract The 3d transition metals were incorporated into SBA-15 matrix by co-condensation synthesis method. Very low concentrations of metals were introduced into silica framework by maintaining the metal to silica ratio in the synthesis gel at 0.01. The difference in hydrolysis rates of metal and silica precursors have led to textural modifications while demonstrating the structural integrity akin to pristine SBA-15. The physicochemical properties obtained offer some insights into the P123 micelle aggregation and mechanism of formation of silica network in the presence of metal salts under similar synthesis conditions of pure SBA-15. The metal doping into SBA-15 leads to increased pore diameters. Higher lattice constants (a<inf>0</inf>) observed in these samples are attributed to the increased pore wall thickness. The significant retention of the hexagonal mesostructure seen in LXRD indicates diminutive influence of metal salts at lower concentrations. Macroscopic morphologies studied by SEM show the formation of spheres along with conventional fibre-like rods. [Figure not available: see fulltext.] © 2015 Indian Academy of Sciences.

Fulltext

Journal of Chemical Sciences

Textural and morphological studies of transition metal doped SBA-15 by co-condensation method

CuNi bimetallic alloy particles supported on CeO2 are prepared by coprecipitation of the corresponding salt precursors followed by calcination and hydrogen reduction. The supported alloy particles are characterized by PXRD, H2-TPR, XPS, XANES and EXAFS techniques. The PXRD study shows that copper rich oxide phases supported on CeO2 are reduced at 200 °C. However, complete reduction of CuO-NiO phases occurs at 450 °C forming CuNi alloy particles on CeO2. The H2-TPR results show that mixed oxides are reduced at higher temperatures than pure components indicating strong wetting between oxide components and CeO2. The Ni 2p XPS shows stronger interaction between Ni2+ and CeO2 support. XANES and EXAFS studies show the formation of CuNi alloy particles with small surface segregation of Cu. The catalytic activity of the supported CuNi alloy particles is studied by non-oxidative dehydrogenation of cyclohexanol to cyclohexanone reaction. The effect of temperature, contact time and time on stream are examined to gain insights into the catalytic activity of the CeO2 supported CuNi alloy catalysts. Among all the CuNi alloy compositions, CuNi(1:1)/CeO2 catalyst shows higher catalytic activity and selectivity to cyclohexanone. Formation of stable CuNi alloy particles on CeO2 by alloy-redox support interaction and segregation of Cu are crucial factors for catalytic activity. © 2012 Elsevier B.V.

Catalysis Today

Nature and catalytic activity of bimetallic CuNi particles on CeO 2 support

Solution combustion synthesis has been used for the preparation of finely dispersed copper oxide, copper and copper-nickel bimetallic particles. The structure and morphology of the materials are studied by XRD and SEM techniques. The fuel content in the combustion mixture is found to be a crucial factor in controlling the formation of oxide and metal particles. Starting with copper nitrate trihydrate as oxidizer (O) and carbohydrazide as fuel (F), we obtained CuO (F/O=0.75-1), mixed valence copper oxides. CuO+Cu2O, (F/O=1.0-1.5) and metallic Cu (F/O=2). At very low fuel content (F/O=0.5), a polymeric phase of copper hydroxide nitrate is isolated from the combustion residue. We also report the use of a new organic fuel N-tertiarybutoxy- carbonylpiperazine for the preparation of Cu, Ni and CuNi bimetallic particles. © 2004 Elsevier B.V. All rights reserved.

Materials Letters

Synthesis of CuO, Cu and CuNi alloy particles by solution combustion using carbohydrazide and N-tertiarybutoxy-carbonylpiperazine fuels

Reaction Kinetics, Mechanisms and Catalysis

Nanogold embedded Co3O4 spinel supported over SBA 15 for the reduction of aquatic pollutant 4-nitrophenol

Chemical Communications

Magnetic-field-induced deposition to fabricate multifunctional nanostructured Co, Ni, and CoNi alloy films as catalysts, ferromagnetic and superhydrophobic materials

New Journal of Chemistry

Catalytic reduction of p-nitrophenol over precious metals/highly ordered mesoporous silica

Synthesis of CuNi and CuNi/SBA-15 by aqueous method at room temperature and their catalytic activity

Journal	Data powered by TypesetMicroporous and Mesoporous Materials
Publisher	Data powered by TypesetElsevier
ISSN	13871811
Open Access	No